Gene Therapy for haemophilia

Gene therapy has the potential to transform life for patients with some bleeding disorders and other debilitating diseases.

Clinical trials undertaken by Professor Amit Nathwani of University College London, Freeline’s Chief Scientific Officer, in conjunction with St. Jude Children’s Research Hospital, and the Royal Free Hospital, and published in The New England Journal of Medicine in December 2011 and November 2014 have demonstrated real hope for haemophilia B patients.

In this study, participants received one of three doses of a gene therapy vector to deliver the genetic material for making Factor IX. The vector was administered as a single infusion into a peripheral vein in the arm of each participant.

Factor IX levels rose in all ten men with severe haemophilia B following gene therapy and have remained stable for more than four years. Use of Factor IX replacement therapy dropped about 92 percent in the first 12 months after the treatment with the investigational therapy.

In the six participants who received the highest gene therapy dose, levels of the blood-clotting protein increased from less than one percent of normal to five percent or more, which resulted in a bleeding episode reduction of over 90%. The increase transformed their disease from severe to mild and enabled participation in sports such as soccer without the need for Factor IX replacement therapy or an increase in the risk of bleeding. Episodes of spontaneous bleeding and use of Factor IX replacement therapy declined for these patients more than 94 percent in the next 12 months.